Mandarin Orange Leaf Problem

Question

Hi- my miniature mandarin orange doesn’t produce fruit. The underside of many leaves has a disgusting looking white and black substance clinging to it. Almost looks like white crystals. Is this Leaf Miner? Please tell me I can blast it with something without destroying the pest’s natural enemies!

Answer 1

It doesn't sound like leaf miners but it could be mealy bugs or scale. The black is sooty mold. Here is more:

https://www.gardeningknowhow.com/edible/fruits/tangerine/mandarin-orange-tree-care.htm

https://www.gardeningknowhow.com/edible/fruits/oranges/no-fruit-on-orange-trees.htm

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=29424

https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm